Cook onion until soft. Add ham and continue cooking until it is browned, about 10 minutes altogether.
Add tomato or V-8 juice and continue cooking until the juice thickens down to about 1/2 its volume. Taste for seasoning and add salt and pepper if necessary.
Add the cooked rice to the ham, onion and juice mixture. Continue cooking for a few minutes to let the rice absorb some of the flavors.